everything is my fault

I dont really know how to start but I guess I am just never okay with myself anymore. Lately I have felt so depressed, I often think about suicide, however I dont think I ever could follow through with it. I know it is unhealthy, and I try not to think of it, but it is always on my mind. I have had a boyfriend for about a year and in the last three months everything has been horrible. When I am about to call him I am in such a terrific mood, but when I begin talking to him he might say something and I just nail him on it and i usually start some argument that somehow i always seem to win. I always think I am right. I know I am stubborn, and I hate it. Afterwards I get so down and I hate myself. I just have been getting so stressed out lately. sometimes I cant stop my leg from shaking, and I always want to cry and scream I am tired of feeling the way I do. Everytime Iget like this i always analyze everything to death. I used to be so happy. Now I am ruining my relationships, not just with my boyfriend but my family and friends as well. please i am so desparate for help.